Loss of lordosis and clinical outcomes after anterior cervical fusion with dynamic rotational plates

Risk Factors of Unplanned Readmission after Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-Analysis

PURPOSE

With an increasing number of anterior cervical discectomy and fusion (ACDF) being conducted for degenerative cervical disc disease, there is a rising interest in the related quality of management and healthcare costs. Unplanned readmission after ACDF affects both the quality of management and medical expenses. This meta-analysis was performed to evaluate the risk factors of unplanned readmission after ACDF to improve the quality of management and prevent increase in healthcare costs.

MATERIALS AND METHODS

We searched the databases of PubMed, EMBASE, Web of Science, and Cochrane Library to identify eligible studies using the searching terms, "readmission" and "ACDF." A total of 10 studies were included.

RESULTS

Among the demographic risk factors, older age [weighted mean difference (WMD), 3.93; 95% confidence interval (CI), 2.30-5.56; p<0.001], male [odds ratio (OR), 1.23; 95% CI, 1.10-1.36; p<0.001], and private insurance (OR, 0.34; 95% CI, 0.17-0.69; p<0.001) were significantly associated with unplanned readmission. Among patient characteristics, hypertension (HTN) (OR, 2.14; 95% CI, 1.41-3.25; p<0.001), diabetes mellitus (DM) (OR, 1.59; 95% CI, 1.20-2.11; p=0.001), coronary artery disease (CAD) (OR, 2.87; 95% CI, 2.13-3.86; p<0.001), American Society of Anesthesiologists (ASA) physical status grade >2 (OR, 2.13; 95% CI, 1.68-2.72; p<0.001), and anxiety and depression (OR, 1.39; 95% CI, 1.29-1.51; p<0.001) were significantly associated with unplanned readmission. Among the perioperative factors, pulmonary complications (OR, 22.52; 95% CI, 7.21-70.41; p<0.001) was significantly associated with unplanned readmission.

CONCLUSION

Male, older age, HTN, DM, CAD, ASA grade >2, anxiety and depression, pulmonary complications were significantly associated with an increased occurrence of unplanned readmission after ACDF.

Comparison of sagittal vertical axis and decompression on the clinical outcome of cervical spondylotic myelopathy

OBJECTIVE

Decompression and cervical balance are major goals in the surgical treatment of cervical spondylotic myelopathy (CSM). Cervical balance is assumed to be a key factor for neurological recovery and pain reduction. Surgical reduction of C2-7 sagittal vertical axis (SVA) correlates with clinical improvement. However, it remains unclear, how much or even if correction is necessary for clinical improvement as long as surgery results in successful decompression. We aim to evaluate the role of radiological cervical balance parameter on the short-term course of CSM.

METHODS

This is a retrospective study with prospectively collected data of 90 patients. The authors identified 45 patients suffering from CSM that underwent decompressive surgery and instrumentation and showed an increased C2-7 sagittal vertical axis (SVA) after surgery. 45 consecutive patients with a decreased C2-7 SVA were selected as a control group.

RESULTS

Surgery improved the clinical outcome of both groups significantly. No differences could be seen comparing neck pain and neurological improvement between both groups. An increased C2-7 SVA did not correlate with an inferior clinical outcome. T1-slope correlated with the Cobb-angle.

CONCLUSIONS

Decompression and stabilization appear to be key elements of surgical treatment of CSM. In short terms, clinical improvement does not appear to affect patients negatively who show a larger C2-7 SVA after surgery. Optimal C2-7 SVA and necessity for a specific C2-7 correction is unclear. The term "balance" remains a complex entity without clear definition.

Multiple level anterior cervical discectomy and fusion versus posterior laminectomy for the management of multilevel cervical spondylotic myelopathy: clinical and radiological outcome

Background

Though both anterior and posterior approach are used for the management of multilevel cervical spondylotic myelopathy (CSM), the choice between both approaches remains to be of considerable debate.

Aim of the work

The aim of the study was to evaluate the clinical and radiographic outcomes of patients with multiple level CSM who underwent posterior laminectomy (PL) versus anterior cervical discectomy and fusion (ACDF).

Methods

This is a retrospective comparative study of 30 patients, with multiple level CSM managed by the authors, either by PL (n = 15) or ACDF (n = 15). Clinical outcome was assessed at 1, 3, 6, and 12 months postoperatively using the modified Japanese Orthopedic Association scale (mJOA) while the postoperative radiographic changes represented by the Cobb’s angle variation was recorded at 12 months postoperatively and compared with preoperative values. Also, the incidence of postoperative complications and neurological deterioration was recorded and studied between the two groups. Study duration was for 2 years from December 2014 to December 2016.

Results

Both the ACDF and PL groups showed an improvement in the mJOA score mean value at 1 year after surgery in comparison with the preoperative evaluation data; however, on comparing between both groups at 1 year postoperatively, the median percent of increase in mJOA score was significantly higher in the ACDF group compared with the PL group (33.3% vs 22.2% respectively). On the other hand, the Cobb’s angle percent of change 1 year after surgery showed a median percent of increase of 18.7% in the ACDF group in contrast to a median decrease of − 11.1% in the PL group which was statistically significant. Minimal complications were reported in both groups.

Conclusion

Both PL and ACDF are effective modalities for the surgical management of multilevel CSM showing good clinical outcome; however, when compared with the posterior approach, there was a statistical significant difference favoring ACDF regarding the median percent of increase in mJOA score and the postoperative Cobb’s angle improvement.

Anterior cervical discectomy and fusion with stand-alone anchored cages versus posterior laminectomy and fusion for four-level cervical spondylotic myelopathy: a retrospective study with 2-year follow-up

Background

The optimal treatment for multi-level cervical spondylotic myelopathy (CSM) remains controversial. Posterior approach is most commonly used, but complicated with insufficient decompression and postoperative axial neck pain. The anterior approach is effective in neural decompression with less surgical trauma. However, the profile of the plate or the possible construct failure may cause dysphagia after surgery. Recently, anterior cervical discectomy and fusion (ACDF) with self-anchored cage is reported to have a superior result over ACDF with anterior plates and screws in three-level CSM. The purpose of the study is to compare the clinical and radiological outcomes of ACDF using stand-alone anchored cages to that of laminectomy with fusion (LF) for treating four-level CSM.

Methods

Twenty-six patients underwent four-level ACDF (Group A) and 32 patients with four-level LF (Group B) were retrospectively reviewed and followed-up for 24 months. Clinical efficacy was evaluated by comparing pre- and post-operative Japanese Orthopedic Association (JOA) and Neck Disability Index (NDI) scores. Operative time, blood loss, fusion, lordosis change and complications were evaluated.

Results

There was significantly less blood loss in Group A (163.4 ± 72.1 ml) than Group B (241.0 ± 112.3 ml) (P < 0.05). Both groups demonstrated significant improvements in JOA and NDI scores after surgery with similar operative time. Improvements in cervical lordosis and fused segment lordosis were more pronounced in Group A (11.3 ± 5.9°, 9.7 ± 5.3°) than Group B (5.8 ± 4.6°, 5.5 ± 4.5°) (P < 0.05). Loss of lordosis in the cervical spine and fused segment was more prominent in Group A (11.7 ± 2.2°, 6.7 ± 3.2°) than Group B (7.5 ± 3.8°, 3.7 ± 3.4°) (P < 0.05) at the final follow-up. Complication rate in Group A and Group B was 57.69 and 18.75%, respectively.

Conclusions

ACDF using a stand-alone anchored cage showed similar clinical results to LF for the treatment of four-level CSM, with better lordosis correction and less blood loss. However, ACDF was associated with more loss of lordosis after surgery and more non-unions.

The influence of sagittal profile alteration and final lordosis on the clinical outcome of cervical spondylotic myelopathy. A Delta-Omega-analysis

Purpose

Decompression and maintaining or restoring a cervical lordosis are major goals in the surgical treatment of cervical spondylotic myelopathy (CSM). Numerous studies support the assumption that cervical lordosis is a key factor for neurological recovery and pain reduction. However, even kyphotic patients can be asymptomatic. The balance of the spine is subject of an increasing number of publications. The main purpose of the study was to evaluate the validity of lordotic alignment on the course of CSM and to set this parameter in context with well-validated tools, namely the modified Japanese Orthopaedic Association scoring system (mJOAS) and the visual analogue scale (VAS), to predict and measure the clinical outcome after surgery.

Methods

This is a retrospective study with prospectively collected data of a heterogeneous cohort. The authors analyzed the records of 102 patients suffering from CSM that underwent decompressive surgery and instrumentation. Clinical outcome was assessed by using the mJOAS, VAS and Odom’s criteria. The radiological analysis involved comparison of pre- and postoperative radiographs. The patients were divided into subgroups to be able to compare the influence of various amounts of correction (3 Delta-groups: <0°, 1–7° and ≥8°) and final lordosis (4 Omega-groups: 0–7°, 8–14°, 15–21°, ≥22°).

Results

219 levels were fused in 102 patients. Surgery improved the clinical outcome of all groups significantly. A lordotic profile was achieved in all analyzed groups. Patients that showed small lordosis after surgery (<8°) did not have an inferior clinical outcome compared to patients with larger cervical lordosis (>14°). The comparison of Odom’s criteria showed that preoperatively kyphotic patients benefitted more from surgery than lordotic patients (p = 0.029), but no differences could be seen comparing neck pain and neurological improvement. The improvement of pain and neurological impairment measured by VAS and mJOAS supports the statistical impact and validity of the data despite comparatively small numbers of patients. The lack of postoperative kyphosis is a major limitation of the study to encompass the impact of sagittal alignment on clinical outcome.

Conclusions

Decompression and stabilization appear to be key elements of surgical treatment of CSM. While the achievement of cervical lordosis remains a major goal of surgery, clinical improvement is not hindered in patients who show small lordosis. However, kyphosis should be eliminated in symptomatic patients. The terms “balance” and “physiologic lordosis” remain complex entities without clear definition. To check the results of our study controlled randomized trials to validate and determine the exact role of cervical balance on the course of CSM would be helpful.

The Effect of Dynamic Versus Static Plating Systems on Fusion Rates and Complications in 1-Level and/or 2-Level Anterior Cervical Discectomy and Fusion: A Systematic Review

STUDY DESIGN

A systematic review.

OBJECTIVE

To determine the effect of plate design on fusion rates in patients undergoing a 1- and 2-level anterior cervical discectomy and fusion (ACDF).

METHODS

Articles published between January 1, 2002 and January 1, 2015 were systematically reviewed to determine the fusion rate of 1- and 2-level ACDFs using either a fully constrained or semiconstrained locking plate. Additional variables that were collected included the number of levels, the type of graft/cage used, the study design, the method for determining fusion, and complications.

RESULTS

Fifty-two articles and 3053 patients were included. No significant difference in the fusion rate for 1- and 2-level ACDF using a fully constrained plate (96.1%) and a semiconstrained plate (95.29%) was identified (P=0.84). No difference (P=0.85) in the total complication rate between fully constrained plates (3.20%) and semiconstrained plates (3.66%), or the rate of complications that required a revision (2.17% vs. 2.41%, P=0.82) was identified. However, semiconstrained plates had a nonsignificant increase in total dysphagia rates (odds ratio=1.660, P=0.28) and short-term dysphagia rates (odds ratio=2.349, P=0.10).

CONCLUSIONS

In patients undergoing a 1- or 2-level ACDF, there is no significant difference in the fusion or complication rate between fully constrained plates and semiconstrained plates.

LEVEL OF EVIDENCE

Level II-systematic review.

Decreased neck muscle strength in patients with the loss of cervical lordosis

BACKGROUND

The loss of cervical lordosis is associated with some negative clinical outcomes. No previous study has examined cervical muscle strength, specifically in patients with the loss of cervical lordosis. This study aims to investigate whether there is weakness of the cervical muscles or an imbalance between cervical flexor and extensor muscle strength in patients with the loss of cervical lordosis compared with healthy controls matched by age, gender, body mass index (BMI), and employment status.

METHODS

Thirty-two patients with the loss of cervical lordosis (23 F, 9 M) and 31 healthy volunteers (23 F, 8 M) were included in the study. Maximal isometric neck extension and flexion strength, and the strength ratio between extension and flexion were used as evaluation parameters. All measurements were conducted by a blinded assessor using a digital force gauge. The participants were positioned on a chair in a neutral cervical position and without the trunk inclined during measurements.

FINDINGS

Maximal isometric neck extension and flexion strength values were significantly lower in the patients versus healthy controls (P<0.001 and P=0.040, respectively). The mean (SD) values of the extension/flexion ratio were 1.21 (0.34) in the patients and 1.46 ± 0.33 in the controls (P=0.004).

INTERPRETATION

According to our results, patients with the loss of cervical lordosis have reduced neck muscle strength, especially in the extensors. These findings may be beneficial for optimizing cervical exercise prescriptions.

A Meta-Analysis of the Incidence of Patient-Reported Dysphagia After Anterior Cervical Decompression and Fusion with the Zero-Profile Implant System

Dysphagia is a well-known complication following anterior cervical surgery. It has been reported that the Zero-profile Implant System can decrease the incidence of dysphagia following surgery, however, dysphagia after anterior cervical decompression and fusion (ACDF) with the Zero-profile Implant System remains controversial. Previous studies only focus on small sample sizes. The objective of this study was to determine the incidence of dysphagia after ACDF with the Zero-profile Implant System. Studies were collected from PubMed, EMBASE, the Cochrane library and the China Knowledge Resource Integrated Database using the keywords "Zero-profile OR Zero-p) AND (dysphagia OR [swallowing dysfunction]". The software STATA (Version 13.0) was used for statistical analysis. Statistical heterogeneity across the various trials, a test of publication bias and sensitivity analysis was performed. 30 studies with a total of 1062 patients were included in this meta-analysis. The occurrence of post-operative transient dysphagia ranged from 0 to 76 % whilst the pooled incidence was 15.6 % (95 % CI, 12.6, 18.5 %). 23 studies reported no persistent dysphagia whilst seven studies reported persistent dysphagia ranging from 1 to 7 %). In summary, the present study observed a low incidence of both transient and persistent dysphagia after ACDF using the Zero-profile Implant System. Most of the dysphagia was mild and gradually decreased during the following months. Moderate or severe dysphagia was uncommon. Future randomized controlled multi-center studies and those focusing on the mechanisms of dysphagia and methods to reduce its incidence are required.

Anterior Cervical Discectomy and Fusion Alters Whole-Spine Sagittal Alignment

PURPOSE

Anterior cervical discectomy and fusion (ACDF) has become a common spine procedure, however, there have been no previous studies on whole spine alignment changes after cervical fusion. Our purpose in this study was to determine whole spine sagittal alignment and pelvic alignment changes after ACDF.

MATERIALS AND METHODS

Forty-eight patients who had undergone ACDF from January 2011 to December 2012 were enrolled in this study. Cervical lordosis, thoracic kyphosis, lumbar lordosis, sagittal vertical axis (SVA), and pelvic parameters were measured preoperatively and at 1, 3, 6, and 12 months postoperatively. Clinical outcomes were assessed using Visual Analog Scale (VAS) scores and Neck Disability Index (NDI) values.

RESULTS

Forty-eight patients were grouped according to operative method (cage only, cage & plate), operative level (upper level: C3/4 & C4/5; lower level: C5/6 & C6/7), and cervical lordosis (high lordosis, low lordosis). All patients experienced significant improvements in VAS scores and NDI values after surgery. Among the radiologic parameters, pelvic tilt increased and sacral slope decreased at 12 months postoperatively. Only the high cervical lordosis group showed significantly-decreased cervical lordosis and a shortened SVA postoperatively. Correlation tests revealed that cervical lordosis was significantly correlated with SVA and that SVA was significantly correlated with pelvic tilt and sacral slope.

CONCLUSION

ACDF affects whole spine sagittal alignment, especially in patients with high cervical lordosis. In these patients, alteration of cervical lordosis to a normal angle shortened the SVA and resulted in reciprocal changes in pelvic tilt and sacral slope.